Terminal land frame and method for manufacturing the same

ABSTRACT

A terminal land frame includes a frame body and a plurality of lands. Each of these lands is formed out of the frame body to be connected to the frame body via a thinned portion and protrude therefrom. When the lands are pressed in a direction in which the lands protrude from the frame body, the thinned portions are fractured and the lands are easily separable from the frame body. A semiconductor chip is mounted on some of the lands of the terminal land frame, and the chip, wires and so on, are single-side-molded with a resin encapsulant. Thereafter, when the lands are pressed on the bottom, the lands are separated from the frame body. As a result, a structure, in which the lower part of each of these lands protrudes downward from the lower surface of the resin encapsulant, is obtained, and that protruding portion is used as an external electrode. In this manner, a downsized and thinned resin-molded semiconductor device is provided at a lower cost and with higher reliability.

BACKGROUND OF THE INVENTION

The present invention relates to a terminal land frame, whichsubstitutes for a conventional leadframe with radial leads and includeslands functioning as external terminals, and also relates to a methodfor manufacturing the same.

In recent years, to catch up with rapidly advancing downsizing ofelectronic units, it has become increasingly necessary to assemblesemiconductor components, like resin-molded semiconductor devices, at ahigher and higher density. Correspondingly, sizes and thicknesses ofsemiconductor components have also been noticeably reduced. In parallelwith this downsizing trend, the number of pins required for a singleelectronic unit is also increasing day after day. To meet these demands,resin-molded semiconductor devices of a greatly reduced size and with adrastically reduced thickness should now be assembled at an even higherdensity.

Hereinafter, a conventional leadframe for a resin-molded semiconductordevice will be described.

FIG. 24 is a plan view illustrating the structure of a conventionalleadframe. As shown in FIG. 24, the conventional leadframe includes: arectangular die pad 102; support leads 103; radial inner leads 104;outer leads 105; and tie bars 106, all of these members being providedinside a frame rail 101. The die pad 102 is used for mounting asemiconductor chip thereon. The support leads 103 support the die pad102. The inner leads 104 are electrically connected to the semiconductorchip mounted with some connection means like metal fine wires. The outerleads 105 are joined to the respective inner leads 104 and to beconnected to external terminals. The tie bars 106 are provided forjoining and fixing the outer leads 105 together and for preventing theoverflow of a resin encapsulant during a resin molding process.

It should be noted that an ordinary leadframe does not consist of asingle pattern such as that shown in FIG. 24, but is made up of aplurality of such patterns, which are arranged to be connected togetherboth horizontally and vertically.

Next, a conventional resin-molded semiconductor device will bedescribed. FIG. 25 is a cross-sectional view illustrating a resin-moldedsemiconductor device using the leadframe shown in FIG. 24.

As shown in FIG. 25, a semiconductor chip 107 is mounted on the die pad102 of the leadframe. The semiconductor chip 107 is electricallyconnected to the inner leads 104 via metal fine wires 108. Thesemiconductor chip 107 on the die pad 102 and the inner leads 104 areencapsulated with a resin encapsulant 109. The outer leads 105 protrudefrom the sides of the resin encapsulant 109 and the ends thereof arebent downward.

Next, a method for manufacturing the conventional resin-moldedsemiconductor device will be described with reference to FIG. 26. First,the semiconductor chip 107 is bonded, with an adhesive, onto the die pad102 of the leadframe. This process step is called “die bonding”. Next,the semiconductor chip 107 is connected to the respective ends of theinner leads 104 via the metal fine wires 108. This process step iscalled “wire bonding”. Subsequently, the semiconductor chip 107 and aportion of the leadframe inside the tie bars 106 (i.e., the inner leads104 and so on) are molded with the resin encapsulant 109 such that theouter leads 105 protrude outward. This process step is called “resinmolding”. Finally, portions slightly inside the tie bars 106 are cut offto separate the outer leads 105 from each other and remove the framerail 101, and the respective ends of the outer leads 105 are bent. Thisprocess step is called “tie bar cutting and bending”. As a result, aresin-molded semiconductor device with the structure shown in FIG. 25 iscompleted. In FIG. 26, a region surrounded by the dashed line is to bemolded with the resin encapsulant 109.

As described above, the number of devices that should be integratedwithin a single semiconductor chip, or the number of pins per chip, hasbeen on the rise these days. In other words, the number of outer leadsshould also be increased to catch up with the latest trend. That is tosay, the number of the inner leads, which are joined to the outer leads,should preferably be increased to cope with such an implementation.However, the width of the inner (or outer) lead has a processable limit.Thus, as the number of inner leads is increased, the overall size of theleadframe and that of the resulting resin-molded semiconductor devicealso increase. That is to say, it is difficult to realize a downsizedand thinned resin-molded semiconductor device in such a case. On theother hand, if only the number of inner leads is increased to cope withthe rise in number of pins of a semiconductor chip while using aleadframe of substantially the same size, then the width of a singleinner lead should be further reduced. In such a case, it becomes moredifficult to perform various process steps for forming the leadframe,like etching, as originally designed.

Recently, semi-face-mount semiconductor devices, such as ball grid array(BGA) types and land grid array (LGA) types, are also provided. Asemiconductor device of such a type is mounted directly on a motherboardon the bottom. Specifically, first, a semiconductor chip is mounted on acarrier (i.e., a printed wiring board) including external electrodes onthe bottom thereof. Next, the semiconductor chip is electricallyconnected to the external electrodes. And then the chip is molded with aresin on the upper surface of the carrier. The semiconductor devices ofthis face-mount type, which is mounted directly on a motherboard on thebottom, will be mainstream products in the near future. Accordingly, itis now clear that the conventional leadframe and resin-moldedsemiconductor device using the leadframe will soon be out of date underthe circumstances such as these.

Also, the conventional resin-molded semiconductor device includes outerleads protruding outward from the sides of a resin encapsulant, and issupposed to be mounted onto a motherboard by bonding the outer leads tothe electrodes of the motherboard. Accordingly, the conventional devicecannot be mounted onto the board so reliably as the semiconductordevices of BGA and LGA types. Nevertheless, the semiconductor devices ofthe BGA and LGA types are more expensive, because these devices use aprinted wiring board. That is to say, it is difficult for any of theseconventional types of semiconductor devices to attain high reliabilityat a low cost.

SUMMARY OF THE INVENTION

An object of the present invention is providing a highly reliableresin-molded semiconductor device at a low cost by taking variousmeasures to mount a semiconductor device onto a board on the bottomusing a frame structure.

To achieve this object, the present inventors take a novel approach,which is totally different from that of the conventional leadframestructure. Specifically, the principal feature of the present inventionlies in a frame structure including a plurality of “lands” to beexternal electrodes, which substitute for the radial “leads” that haveheretofore been adopted widely.

Another object of the present invention is manufacturing a resin-moldedsemiconductor device more easily and at a lower cost by eliminating theprocess steps of cutting and bending the leads.

A first exemplary terminal land frame according to the present inventionincludes: a frame body; a plurality of lands, each said land beingsubstantially as thick as the frame body, at least part of each saidland protruding out of the frame body; and a plurality of thinnedportions, each said thinned portion connecting the frame body toassociated one of the lands and being thinner than the frame body or thelands. When each said land is pressed in a direction in which the landprotrudes, associated one of the thinned portions is fractured and theland is separable from the frame body.

A terminal land frame with such a structure is applicable tomanufacturing a resin-molded semiconductor device in which part of eachland, which protrudes from the lower surface of a resin encapsulant, canbe used as an external electrode.

In one embodiment of the present invention, the top of that part of eachsaid land, which protrudes from the frame body, is preferably laterallyexpanded and shaped like a mushroom.

In another embodiment, the frame body, the lands and the thinnedportions are preferably all made of a single metal plate.

In still another embodiment, the top face of the part of each said land,which protrudes from the frame body, is preferably greater in area thananother face of the land, which is opposite to the top face. And the topface preferably has curved edges.

A second exemplary terminal land frame according to the presentinvention includes: a frame body; a die pad being substantially as thickas the frame body and including a first part protruding out of the framebody; a plurality of lands, each said land being substantially as thickas the frame body and including a second part protruding out of theframe body; a first thinned portion connecting the frame body and thedie pad together and being thinner than the frame body or the die pad;and a plurality of second thinned portions, each said second thinnedportion connecting the frame body to associated one of the lands andbeing thinner than the frame body or the lands. When the die pad andeach said land are pressed in a direction in which the die pad and theland protrude, the first thinned portion and associated one of thesecond thinned portions are fractured and the die pad and the land areseparable from the frame body.

A terminal land frame including a die pad can also attain the sameeffects as those of the first terminal land frame.

The same preferred embodiments as those applied to the first terminalland frame are also applicable to the second terminal land frame.

A first exemplary method for manufacturing a terminal land frameaccording to the present invention includes the steps of: a) placing ametal plate, which will be wrought into a frame body, on a blanking dieand pressing the metal plate downward with a presser die; and b)pressing a plurality of parts of the metal plate downward with ablanking member such that each of these parts pressed protrudes out ofthe body of the metal plate into associated one of openings of theblanking die, thereby forming a plurality of lands out of these partsand forming a plurality of half-cut thinned portions connecting thelands to the metal plate body.

According to the first method, the first terminal land frame of thepresent invention can be manufactured easily.

In one embodiment of the present invention, the blanking memberpreferably has a plurality of punches in the step a), each having across-sectional area smaller than that of associated one of the openingsof the blanking die. And the step b) is preferably performed such thatthe top face of each said part, which protrudes from the metal platebody, is greater in area than another face of the part, which isopposite to the top face, and that the top face of each said part hascurved edges.

A second exemplary method for manufacturing a terminal land frameaccording to the present invention includes the steps of: a) placing ametal plate, which will be wrought into a frame body, on a blanking dieand pressing the metal plate downward with a presser die; and b)pressing a first region and a plurality of second regions of the metalplate downward with a blanking member such that a first part at thefirst region and a second part at each said second region protrude outof the body of the metal plate into associated openings of the blankingdie, thereby forming a die pad at the first region, a half-cut firstthinned portion connecting the die pad to the metal plate body, aplurality of lands at the second regions and a plurality of half-cutsecond thinned portions connecting the lands to the metal plate body.

According to the second method, the second terminal land frame of thepresent invention can be manufactured easily.

In one embodiment of the present invention, the blanking memberpreferably has a plurality of punches in the step a), each having across-sectional area smaller than that of associated one of the openingsof the blanking die. The step b) is preferably performed such that thetop face of the first part at the first region is greater in area thananother face of the first part, which is opposite to the top face, andthat the top face of the first part has curved edges. And the step b) isalso preferably performed such that the top face of the second part ateach said second region is greater in area than another face of thesecond part, which is opposite to the top face, and that the top face ofthe second part has curved edges.

A first resin-molded semiconductor device according to the presentinvention is formed by using a terminal land frame, which includes: ametallic frame body; a plurality of lands including first and secondgroups of lands, each said land being substantially as thick as theframe body, at least part of each said land protruding out of the framebody; and a plurality of thinned portions, each said thinned portionconnecting the frame body to associated one of the lands and beingthinner than the frame body or the lands. The semiconductor deviceincludes: a semiconductor chip being mounted on the first group of landsand having a plurality of electrode pads; a plurality of connectionmembers, each said connection member electrically connecting each saidland of the second group to associated one of the electrode pads; and aresin encapsulant for molding the semiconductor chip, the connectionmembers and respective upper halves of the lands, each said upper halfcorresponding to the part of the associated land that protrudes out ofthe frame body. The lower half of each said land other than the upperhalf thereof is not covered with the resin encapsulant but protrudesdownward out of the lower surface of the resin encapsulant.

In this structure, the lower halves of the lands protruding out of thelower surface of the resin encapsulant can be used as the externalelectrodes, which can be disposed at arbitrary positions on the lowersurface of the resin-molded semiconductor device. Thus, a highlyreliable, thinned and downsized resin-molded semiconductor device can bemanufactured at a lower cost by a high-density mount technique.

In one embodiment of the present invention, the top face of the upperhalf of each said land, which is buried in the resin encapsulant, ispreferably greater in area than the bottom face of the lower halfthereof, and the top face of the upper half preferably has curved edges.

A second resin-molded semiconductor device according to the presentinvention is formed by using a terminal land frame, which includes: ametallic frame body; a die pad being substantially as thick as the framebody and including a first part protruding out of the frame body; aplurality of lands, each said land being substantially as thick as theframe body and including a second part protruding out of the frame body;a first thinned portion connecting the frame body and the die padtogether and being thinner than the frame body or the die pad; and aplurality of second thinned portions, each said second thinned portionconnecting the frame body to associated one of the lands and beingthinner than the frame body or the lands. The semiconductor deviceincludes: a semiconductor chip being mounted on the die pad and having aplurality of electrode pads; a plurality of connection members, eachsaid connection member electrically connecting each said land toassociated one of the electrode pads of the semiconductor chip; and aresin encapsulant for molding the semiconductor chip, the connectionmembers, a first upper half corresponding to the first part of the diepad protruding out of the frame body, and respective second upper halvescorresponding to the second parts of the lands protruding out of theframe body. A first lower half, which is the remaining portion of thedie pad other than the first upper half, and second lower halves, eachof which is the remaining portion of associated one of the lands otherthan associated one of the second upper halves, are not covered with theresin encapsulant but protrude downward out of the lower surface of theresin encapsulant.

A resin-molded semiconductor device with such a structure can dissipatea sufficient amount of heat using the die pad and can also attain thesame effects as those of the first resin-molded semiconductor device.

In one embodiment of the present invention, the top face of the firstupper half of the die pad, which is buried in the resin encapsulant, ispreferably greater in area than the bottom face of the first lower halfthereof, and the top face of the first upper half preferably has curvededges. The top face of the second upper half of each said land, which isburied in the resin encapsulant, is preferably greater in area than thebottom face of the second lower half thereof, and the top face of thesecond upper half preferably has curved edges.

A third resin-molded semiconductor device according to the presentinvention is formed by using a terminal land frame, which includes: ametallic frame body; a plurality of lands, each said land beingsubstantially as thick as the frame body, at least part of each saidland protruding out of the frame body; and a plurality of thinnedportions, each said thinned portion connecting the frame body toassociated one of the lands and being thinner than the frame body or thelands. The semiconductor device includes: a semiconductor chip beingmounted on the lands and having a plurality of electrode pads connectedto the lands; and a resin encapsulant for molding the semiconductor chipand respective upper halves of the lands, each said upper halfcorresponding to the part of the associated land that protrudes out ofthe frame body. The lower half of each said land other than the upperhalf thereof is not covered with the resin encapsulant but protrudesdownward out of the lower surface of the resin encapsulant.

A resin-molded semiconductor device with such a flip-chip mountedstructure can attain the same effects as those of the first resin-moldedsemiconductor device.

In one embodiment of the present invention, the top face of the upperhalf of each said land, which is buried in the resin encapsulant, ispreferably greater in area than the bottom face of the lower halfthereof, and the top face of the upper half preferably has curved edges.

In another embodiment, the third resin-molded semiconductor devicepreferably further includes: the same number of protruding electrodes asthat of the electrode pads of the semiconductor chip, each saidprotruding electrode being formed on associated one of the electrodepads; and a conductive adhesive for electrically connecting theprotruding electrodes to the lands.

A first method for manufacturing a resin-molded semiconductor deviceaccording to the present invention includes the step of a) preparing aterminal land frame, which includes: a frame body; a plurality of landsincluding first and second groups of lands, each said land beingsubstantially as thick as the frame body, at least part of each saidland protruding out of the frame body; and a plurality of thinnedportions, each said thinned portion connecting the frame body toassociated one of the lands and being thinner than the frame body or thelands. When each said land is pressed in a direction in which the landprotrudes, associated one of the thinned portions is fractured and theland is separable from the frame body. The method further includes thesteps of: b) mounting a semiconductor chip on respective top faces ofthe protruding parts of the first group of lands; c) electricallyconnecting the lands of the second group to associated electrode pads ofthe semiconductor chip via a plurality of connection members; d) moldingthe semiconductor chip, the connection members and the upper half of theterminal land frame, including the respective parts of the landsprotruding out of the frame body, with a resin encapsulant; and e)applying force in such a direction as separating the respective membersmolded with the resin encapsulant, including the lands, from the framebody, thereby separating a resin-molded semiconductor device, in whichrespective lower halves of the lands other than the protruding partsthereof are not covered with the resin encapsulant but protrude downwardfrom the lower surface of the resin encapsulant, from the frame body.

According to this method, the first resin-molded semiconductor devicecan be manufactured easily while preventing resin bur from reaching thebottoms of the lands during resin molding and ensuring a standoff heightlarge enough to use the lands as external electrodes.

In one embodiment of the present invention, respective faces of at leastpart of the lands, which faces are opposite to the top faces of theprotruding parts of the lands, are preferably pressed toward the topfaces in the step e).

A second method for manufacturing a resin-molded semiconductor deviceaccording to the present invention includes the steps of: a) preparing aterminal land frame, which includes: a metallic frame body; a die padbeing substantially as thick as the frame body and including a firstpart protruding out of the frame body; a plurality of lands, each saidland being substantially as thick as the frame body and including asecond part protruding out of the frame body; a first thinned portionconnecting the frame body and the die pad together and being thinnerthan the frame body or the die pad; and a plurality of second thinnedportions, each said second thinned portion connecting the frame body toassociated one of the lands and being thinner than the frame body or thelands; b) mounting a semiconductor chip on the top face of theprotruding first part of the die pad; c) electrically connecting thelands to associated electrode pads of the semiconductor chip via aplurality of connection members; d) molding the semiconductor chip, theconnection members and the upper half of the terminal land frame,including the first part of the die pad and the second parts of thelands, with a resin encapsulant; and e) applying force in such adirection as separating the respective members molded with the resinencapsulant, including the die pad and the lands, from the frame body,thereby separating a resin-molded semiconductor device, in which a firstlower half, which is the remaining portion of the die pad other than thefirst part, and second lower halves, each of which is the remainingportion of associated one of the lands other than associated one of thesecond parts, are not covered with the resin encapsulant but protrudedownward from the lower surface of the resin encapsulant, from the framebody.

According to this method, the second resin-molded semiconductor devicecan be manufactured easily while preventing resin bur from reaching thebottoms of the lands during resin molding and ensuring a standoff heightlarge enough to use the lands as external electrodes.

In one embodiment of the present invention, a face of the die pad, whichface is opposite to the top face of the first part, is preferablypressed toward the top face, and respective faces of at least part ofthe lands, which faces are opposite to the top faces of the secondparts, are preferably pressed toward the top faces in the step e).

A third method for manufacturing a resin-molded semiconductor deviceaccording to the present invention includes the step of a) preparing aterminal land frame, which includes: a metallic frame body; a pluralityof lands, each said land being substantially as thick as the frame body,at least part of each said land protruding out of the frame body; and aplurality of thinned portions, each said thinned portion connecting theframe body to associated one of the lands and being thinner than theframe body or the lands. When each said land is pressed in a directionin which the land protrudes, associated one of the thinned portions isfractured and the land is separable from the frame body. The methodfurther includes the steps of: b) mounting a semiconductor chip onrespective top faces of the protruding parts of the lands, therebyelectrically connecting the lands to associated electrode pads of thesemiconductor chip; c) molding the semiconductor chip and the upper halfof the terminal land frame, including the respective parts of the landsprotruding out of the frame body, with a resin encapsulant; and d)applying force in such a direction as separating the respective membersmolded with the resin encapsulant, including the lands, from the framebody, thereby separating a resin-molded semiconductor device, in whichrespective lower halves of the lands other than the protruding partsthereof are not covered with the resin encapsulant but protrude downwardfrom the lower surface of the resin encapsulant, from the frame body.

According to this method, the third resin-molded semiconductor devicecan be manufactured easily while preventing resin bur from reaching thebottoms of the lands during resin molding and ensuring a standoff heightlarge enough to use the lands as external electrodes.

In one embodiment of the present invention, respective faces of at leastpart of the lands, which faces are opposite to the top faces of theprotruding parts of the lands, are preferably pressed toward the topfaces in the step d).

In another embodiment, protruding electrodes, which are formed on therespective electrode pads of the semiconductor chip, are preferablyelectrically connected to the lands with a conductive adhesive in thestep b).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a terminal land frame according to a firstembodiment of the present invention.

FIG. 2 is a cross-sectional view of the frame taken along the line II—IIin FIG. 1.

FIG. 3 is a cross-sectional view illustrating a land shown in FIG. 2 toa larger scale.

FIG. 4 is a cross-sectional view illustrating a state just before ahalf-blanking step is performed during a manufacturing process of aterminal land frame according to the present invention.

FIG. 5 is a cross-sectional view illustrating the half-blanking stepduring the manufacturing process of the terminal land frame according tothe present invention.

FIG. 6 is a cross-sectional view illustrating land, metal plate andthinned portion where a half-cut state has been established by theapplication of pressure to part of the metal plate using a blankingmember in the half-blanking step according to the present invention.

FIG. 7 is a cross-sectional view of the device taken along the lineVII—VII shown in FIG. 8.

FIG. 8 is a bottom view of a resin-molded semiconductor device accordingto the first embodiment.

FIGS. 9(a) through 9(f) are cross-sectional views illustratingrespective process steps for manufacturing the resin-moldedsemiconductor device according to the first embodiment.

FIG. 10 is a plan view of a terminal land frame according to a secondembodiment of the present invention.

FIG. 11 is a cross-sectional view of the frame taken along the lineXI—XI shown in FIG. 10.

FIG. 12 is a cross-sectional view of the device taken along the lineXII—XII shown in FIG. 13.

FIG. 13 is a bottom view of a resin-molded semiconductor deviceaccording to the second embodiment.

FIGS. 14(a) through 14(f) are cross-sectional views illustratingrespective process steps for manufacturing the resin-moldedsemiconductor device according to the second embodiment.

FIG. 15 is a plan view of a terminal land frame according to a thirdembodiment of the present invention.

FIG. 16 is a cross-sectional view of the frame taken along the lineXVI—XVI shown in FIG. 15.

FIG. 17 is a cross-sectional view illustrating a land shown in FIG. 16to a larger scale.

FIG. 18 is a plan view of a semiconductor chip used in the thirdembodiment.

FIG. 19 is a plan view of a semiconductor chip used in a modifiedexample of the third embodiment.

FIG. 20 is a plan view of a terminal land frame applicable to asemiconductor chip with electrode pads arranged around the peripherythereof such as that shown in FIG. 19.

FIG. 21 is a cross-sectional view of the device taken along the lineXXI—XXI shown in FIG. 22.

FIG. 22 is a bottom view of a resin-molded semiconductor deviceaccording to the third embodiment.

FIGS. 23(a) through 23(e) are cross-sectional views illustratingrespective process steps for manufacturing the resin-moldedsemiconductor device according to the third embodiment.

FIG. 24 is a plan view of a conventional leadframe.

FIG. 25 is a cross-sectional view of a conventional resin-moldedsemiconductor device.

FIG. 26 is a plan view illustrating a method for manufacturing theconventional resin-molded semiconductor device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1

FIG. 1 is a plan view of a terminal land frame according to a firstembodiment of the present invention. FIG. 2 is a cross-sectional view ofthe frame taken along the line II—II shown in FIG. 1. FIG. 3 is across-sectional view illustrating a land shown in FIG. 2 to a largerscale.

As shown in FIGS. 1 through 3, a terminal land frame according to thefirst embodiment includes a frame body 10, which is a metal plate madeof copper or Alloy 42 that is used widely for leadframes. The terminalland frame further includes a plurality of lands 12, which are arrangedon the frame body 10 to form a matrix pattern, connected to the framebody 10 via respective thinned portions 11 and protrude upward out ofthe frame body 10. That is to say, the frame body 10, lands 12 andthinned portions 11 are all made of a single metal plate. The terminalland frame is formed in such a manner that when a land 12 is pressedupward on the bottom 12 a, the thinned portion 11 is fractured and theland 12 is separable from the frame body 10. Also, as shown in FIG. 1, alarge number of lands 12 are arranged to form a matrix pattern in itsplanar layout. Alternatively, these lands 12 may be arranged to form ahound's-tooth check or checkerboard fashion or may be arranged at randomin its planar layout. That is to say, any arbitrary arrangement may beemployed so long as the arrangement is suitable for connecting the landsto a semiconductor chip to be mounted thereon via metal fine wires.

As shown in FIG. 3, when the land 12 is pressed on the bottom 12 a insuch a direction as protruding the land 12 upward, the thinned portion11 as indicated by the broken line is fractured, and the land 12 isseparated from the frame body 10. In this case, the thinned portion 11is a “linkage portion” formed by half-blanking the frame body 10 itselfusing a half-cutting member. That is to say, when part of the frame body10, in which a land is to be formed, is blanked using a blanking member,that part is not blanked through completely, but blanking is stoppedpreferably at around a midway point. As a result, that half-blanked partprotrudes out of the frame body 10 to form the land 12. And a portionlinking the land 12 to the frame body 10 is also formed as the thinnedportion 11. Accordingly, the thinned portion 11 is so thin that when theland 12 is pressed on the bottom 12 a in such a direction as protrudingthe land 12 upward, the thinned portion 11 is fractured easily.

The protrusion height of the land 12 as measured from the upper surfaceof the frame body 10 is a half or more of the thickness of the framebody 10 itself. That is to say, the frame body 10 is formed in such amanner that when a land 12 is pressed on the bottom 12 a upward in FIG.2, the thinned portion 11 is fractured and the land 12 is separable fromthe frame body 10.

For example, according to this embodiment, the thickness of the terminalland frame itself, i.e., the thickness of the frame body 10, may be 200μm. On the other hand, the protrusion height of the land 12 may be inthe range from 140 μm to 180 μm, which is 70 to 90% of the thickness ofthe frame body 10. It should be noted that the thickness of the framebody 10 does not have to be 200 μm, but may be about 400 μm ifnecessary. Also, according to this embodiment, the protrusion height ofthe land 12 is supposed to be a half or more of the thickness of theframe body, e.g., 70 to 90% of the thickness of the frame body.Alternatively, the protrusion height may be less than a half of thethickness of the frame body. At any rate, the protrusion height may bedefined at such a value as making the thinned portion 11 fracturableupon the application of pressure.

Also, according to this embodiment, the terminal land frame is platedwith a plurality of metal layers, e.g., nickel (Ni), palladium (Pd) andgold (Au) layers stacked one upon the other. In this manner, theterminal land frame may be plated if necessary. Plating the terminalland frame may be performed either after or before the metal plate isshaped to form the lands 12. Moreover, the roughness at the surface ofthe terminal land frame according to this embodiment is 0.1 μm or less.Although the surface of the terminal land frame never fails to getrugged by the formation of the lands 12, the surface roughness of theterminal land frame because of other reasons is preferably as small aspossible. This is because the roughness affects the ease of peeling theterminal land frame from a resin during resin molding.

Furthermore, in the terminal land frame according to this embodiment,the top of the protruding part of the land 12 is somewhat expandedlaterally as a result of a type of pressing called “coining”.Accordingly, the upper surface of the land 12 is shaped flat like thatof a mushroom. Thus, when a semiconductor chip is mounted on theterminal land frame and molded with a resin, the lands 12 can be heldmore strongly by the resin encapsulant because the lands 12 are shapedlike mushrooms. As a result, the lands 12, can be in tighter contactwith the resin encapsulant, thus realizing highly reliable resin moldingin spite of the single-side-molded structure thereof. It is noted thatthe protruding part of the land 12 does not have to have its uppersurface flattened like a mushroom, but may be in any arbitrary shape,e.g., like a crook, so long as the resin encapsulant can be anchored bythe land 12.

The terminal land frame according to the present invention is notprovided with any die pad, which is a member usually used for mounting asemiconductor chip thereon, on purpose. Instead, a number of the lands12, which are provided in respective regions of the frame body 10, maybe used as the die pad. That is to say, a semiconductor chip may besupported on a number of lands 12. Accordingly, the terminal land framecan mount a semiconductor chip of any type thereon even if the sizesthereof are different from each other. Specifically, an appropriatenumber of lands 12, which are selected from the group of lands dependingon the size of a chip to be mounted, may be used for supporting the chipthereon, and the other lands 12 may be used to establish electricalconnection with the semiconductor chip mounted. That is to say, theterminal land frame is commonly applicable to various types ofresin-molded semiconductor devices. Also, even when semiconductor chipsof different sizes are mounted on a single frame and then molded with aresin encapsulant at the same time, desired resin-molded semiconductordevices can be obtained at a time.

The number of the lands 12 may be appropriately defined depending on thenumber of pins of the semiconductor chip to be mounted. Also, as shownin FIG. 1, the lands 12 may be successively formed out of the frame body10 both horizontally and vertically alike. Furthermore, the land 12 doesnot have to be circular as viewed from above, but may be polygonal orrectangular. All the lands 12 within the terminal land frame may be ofthe same size. Moreover, when a resin-molded semiconductor device isformed with this terminal land frame using the lands 12 as landelectrodes, only some of the lands 12 located around the periphery maybe larger than the other lands 12 to relax a stress, which is causedwhen the device is mounted onto a motherboard. The upper surface of theland 12 may be of such a size that a semiconductor chip can be bondedthereto via a metal fine wire like a gold wire. In this embodiment, thesize may be 100 μmφ or more.

The terminal land frame according to the first embodiment includes noneof the conventional members called “inner leads”, “outer leads” and “diepad”. Instead, the terminal land frame includes lands 12 functioning asland electrodes, which are arranged to form a matrix or hound's-toothpattern in its planar layout. Thus, a resin-molded semiconductor deviceincluding land electrodes on its bottom can be obtained easily by usingthis terminal land frame as will be described in detail later. Inaddition, according to this embodiment, the members functioning asexternal electrodes of a resin-molded semiconductor device are notradial leads as in a conventional leadframe, but dotted lands 12. Thus,these lands 12 may be disposed at any arbitrary positions in the planarlayout. Accordingly, these lands 12 may be placed more freely as theexternal electrodes for a resin-molded semiconductor device, and it ispossible to cope with the increase in number of pins of a semiconductorchip. The arrangement pattern of the lands 12 is arbitrarily selectablein accordance with the number of pins of a semiconductor chip to bemounted. Thus, it is naturally possible to arrange the lands 12 in lineas in the conventional leadframe.

Next, a method for manufacturing a terminal land frame according to thisembodiment will be described.

FIGS. 4 and 5 are cross-sectional views illustrating how the land 12 isformed by a half-blanking step during a manufacturing process of theterminal land frame.

First, as shown in FIG. 4, a metal plate 13 to be wrought into the framebody of a terminal land frame is placed on a blanking die 14 and thenpressed downward with a presser die 15. In FIG. 4, the die 14 isprovided with an opening 16 to receive the blanked portion and ablanking member, which are both pressed downward. The blanking member 17is disposed above the metal plate 13.

Next, as shown in FIG. 5, the metal plate 13, which has been fixed at apredetermined position on the die 14, is pressed downward with theblanking member 17. In this manner, part of the metal plate 13 isprotruded into the opening 16 of the die 14 and portion of the metalplate 13, with which the blanking member 17 is now in contact, ishalf-cut, thereby forming the land 12. That is to say, the land 12 isformed to remain connected to the metal plate 13 via the thinned portion11 and to protrude from the body of the metal plate 13. It should benoted that the number of the blanking member 17 is not necessarily one.Rather, it is more common to form a plurality of lands 12 at a timeusing a plurality of blanking members 17 simultaneously.

According to this embodiment, when part of the metal plate 13 ishalf-blanked with the blanking member 17, that part is not completelyblanked, but the blanking member 17 is made to stop pressing at a midwaypoint, thereby making that part of the metal plate 13 half-cut.Accordingly, that part of the metal plate 13 that has been pressed bythe blanking member 17 is not separated from the metal plate 13 yet, butremains connected to the body of the metal plate 13. Also, the area ofcontact between that part of the metal plate 13, where the land 12should be formed, and the blanking member 17 is smaller than the area ofthe opening 16 provided for the die 14. Furthermore, in the process stepof forming the land 12 to protrude from the metal plate 13 by gettingthat part of the metal plate 13 pressed by the blanking member 17, theupper surface 12 b of the land 12 protruding from the upper surface ofthe metal plate 13 is greater in area than the bottom 12 a of the land12 formed out of the backside of the metal plate 13. Thus, the edges ofthe upper surface 12 a are curved, because these edges are plasticallydeformed and rounded.

In this structure, when the land 12 formed in this way is pressed in thedirection in which the land 12 protrudes, i.e., when a pressure isapplied to the bottom 12 a of the land 12, the land 12 is easilyseparable from the body of the metal plate 13. on the other hand, evenwhen a pressure is applied to the upper surface 12 b of the land 12, theland 12 is less likely to be separated from the metal plate 13. In otherwords, the land 12 is easily separable only by unidirectional pressure.

Also, if the protruding upper part of the land 12 is shaped by apressing process called “coining”, the protruding part of the land 12can be shaped like a mushroom with a flat upper surface and laterallyexpanded upper edges. The land 12 is shaped like a mushroom by thecoining process. Accordingly, if a semiconductor chip is mounted on theterminal land frame and is molded with a resin encapsulant, then thelands 12 are held by the resin encapsulant more strongly. Since themushroom-like lands 12 attain anchoring effects in this manner, the chipcan be in even tighter contact with the resin encapsulant. Thus,although the resin-molded semiconductor device is of asingle-side-molded type, high reliability is attained as a result of theresin molding process.

According to this embodiment, when the lands 12 are formed out of themetal plate 13, the protrusion height of the lands 12 (i.e., a leveldifference between the upper surface of the lands 12 and that of themetal plate 13) is preferably a half or more of the thickness of themetal plate 13 itself. In this embodiment, the thickness of the metalplate 13 may be 200 μm, while the protrusion height of the lands 12 maybe in the range from 140 μm to 180 μm, which is 70 to 90% of thethickness of the metal plate 13 itself. Accordingly, the land 12protruding from the metal plate 13 is connected to the body of the metalplate 13 via the thinned portion 11 with a very small thickness. In thisembodiment, the thickness of the thinned portion 11 may be in the rangefrom 20 μm to 60 μm, which is 10 to 30% of the thickness of the metalplate 13 itself. If the thickness of the thinned portion 11 is definedwithin this range, then the land 12 is easily separable from the metalplate 13 by applying a pressure to the land 12 in the direction in whichthe land 12 protrudes.

It should be noted that the thickness of the metal plate 13 for theterminal land frame does not have to be 200 μm, but may be about 400 μmif necessary. Similarly, although the protrusion height of the lands 12is supposed to be a half or more of the thickness of the metal plate 13according to this embodiment, the protrusion height may be less than ahalf of the thickness of the metal plate 13. At any rate, the protrusionheight may be defined at such a value as making the thinned portion 11easily fracturable upon the application of a pressure after thesemiconductor chip and so on have been molded with a resin encapsulant.

Hereinafter, a half-cutting process for forming the lands 12 accordingto the first embodiment will be described. FIG. 6 is a cross-sectionalview illustrating the land 12, metal plate 13 and thinned portion 11where a half-cut state has been established by the application of apressure to part of the metal plate 13 using a blanking member.

As shown in FIG. 6, after the land 12 has been formed out of the metalplate 13, the metal plate 13 is divisible into a plastically deformedportion 18, a shear strained portion 19 and a fracturable portion 20.The plastically deformed portion 18 is formed as a result of thehalf-blanking process using the blanking member 17 shown in FIGS. 4 and5. The shear strained portion 19 has received shear strain from theblanking member 17. And the fracturable portion 20 includes a fractureplane, which will make the land 12 easily separable upon the applicationof a pressure to the land 12 in which the land 12 protrudes.

When the lands 12 are formed through the half-blanking process using theblanking members 17, the plastically deformed, shear strained andfracturable portions 18, 19 and 20 are formed in this order. Thefracturable portion 20 corresponds to the thinned portion 11. In FIG. 6,the fracturable portion 20 is illustrated as being relatively thick,since this is just a model representation. Actually, however, thefracturable portion 20 is very thin. Also, in the process step ofhalf-cutting the metal plate 13, the size ratio of the portions A and Bshown in FIG. 6 is ideally 1:1. That is to say, this is a state wherethe half-blanking process is finished by making the blanking member 17stop at a point in time half of the metal plate 13 has been blanked bythe blanking member 17. It should be noted that the size ratio A:B isappropriately modifiable depending on the thickness of the metal plate13.

Furthermore, the thickness ratio of the shear strained portion 19 to thefracturable portion 20 is controllable by changing the size of aclearance created during the half-blanking process. In thisspecification, the “clearance” is the lateral width of a gap, which isvariable with the difference in lateral width between the blankingmember 17 and the opening 16 of the die 14. Specifically, if theclearance is reduced, then the shear strained portion 19 can be thickerthan the fracturable portion 20. Conversely, if the clearance isincreased, then the shear strained portion 19 can be thinner than thefracturable portion 20. Accordingly, if the thickness of the fracturableportion 20 is minimized by eliminating the clearance, the end of themetal plate half-blanking process can be delayed. In such a case, evenafter the blanking member has reached farther than a halfway point ofthe metal plate 13, the half-cutting process does not have to befinished.

Also, the cross-sectional area of the blanking member may be larger thanthat of the opening 16 of the die 14. This is because the half-cutthinned portion can also be formed even in such a case if the blankingmember 17 is stopped before the blanking member 17 reaches the uppersurface of the die 14.

Next, a preferred embodiment of the resin-molded semiconductor deviceaccording to the present invention will be described with reference tothe accompanying drawings. FIGS. 7 and 8 are cross-sectional view andbottom view, respectively, of the resin-molded semiconductor deviceaccording to the first embodiment. FIG. 7 is a cross-sectional view ofthe device taken along the line VII—VII shown in FIG. 8. Theresin-molded semiconductor device according to this embodiment is in asimple rectangular shape as viewed from above. Thus, the illustration ofa plan view thereof is omitted herein.

As shown in FIGS. 7 and 8, the resin-molded semiconductor deviceaccording to this embodiment includes a semiconductor chip that has beenmounted using the terminal land frame. A plurality of lands 21 a through21 f shown in FIG. 7 are classified into first and second groups.Specifically, a semiconductor chip 23 is mounted on the lands 21 a and21 b of the first group with a conductive adhesive 22 such as silverpaste (or insulating paste). On the other hand, the lands 21 c, 21 d, 21e and 21 f of the second group, which are located around the peripheryof the semiconductor chip 23, are electrically connected to thesemiconductor chip 23 via metal fine wires 24. Also, the lower half ofeach of these lands 21 a through 21 f protrudes downward from the lowersurface of a resin encapsulant 25. And the semiconductor chip 23,conductive adhesive 22, metal fine wires 24 and respective parts of thelands 21 a through 21 f are molded with the resin encapsulant 25.

According to this embodiment, the height of the lower part of each land21 protruding from the lower surface of the resin encapsulant 25 issubstantially equal to the thickness B of the fracturable portion 20shown in FIG. 6, and is obtained by subtracting the protrusion height Aof the land 21 from the total thickness C of the terminal land frame.This protrusion height of the lower part of the land 21 corresponds to astandoff height required in mounting the resin-molded semiconductordevice on a motherboard.

In the resin-molded semiconductor device according to this embodiment,the lands 21 a and 21 b of the first group, selected from the lands 21 athrough 21 f, are used as a die pad for supporting the semiconductorchip 23 thereon. The other lands 21 c through 21 f of the second groupare used as external electrodes. On the bottom of the resin-moldedsemiconductor device, the lands 21 are arranged to form a land gridarray. And depending on the size and the number of pins of asemiconductor chip to be mounted, the number of the lands 21 used forsupporting the semiconductor chip and the number of the lands 21 used asexternal electrodes can be appropriately defined.

Also, unlike the resin-molded semiconductor device using a leadframe,the area of the land 21 only needs to be large enough to be wire-bonded(preferably, the diameter thereof should be 100 μm or more) in theresin-molded semiconductor device according to this embodiment. And theprotrusion height (i.e., the standoff height) of the land 21 should beonly about 20 μm to about 60 μm. Accordingly, electrode pads (not shown)can be arranged at a high density on the upper surface of thesemiconductor chip, thus realizing a downsized and thinned resin-moldedsemiconductor device. Moreover, the structure according to thisembodiment can cope with multiple-pin implementation and contribute tothe realization of a high-density face-mount resin-molded semiconductordevice. Furthermore, even after resin molding has been performed, theresin-molded semiconductor device can be as thin as 1 mm or less, e.g.,about 500 μm.

In addition, in the resin-molded semiconductor device according to thisembodiment, the end face of the land 21, which is covered (or molded)with the resin encapsulant, is greater in area than the opposite endface thereof, which is not covered with the resin encapsulant 25 butprotrudes. Furthermore, the edge portions of the molded end face of theland 21 are curved (i.e., plastically deformed). Accordingly, in thestate shown in FIG. 7, the land 21 is substantially of an invertedtrapezoidal cross-sectional shape. By using such a structure, the land21 can be held by the resin encapsulant 25 more strongly and can be intighter contact with the resin encapsulant 25. In addition, the assemblycan be mounted onto a motherboard with sufficiently high connectionreliability maintained. Furthermore, if the thickness of the terminalland frame used is increased, then the contact area between the land 21and the resin encapsulant 25 can be increased, thus enhancing theanchoring effects. As a result, the reliability can be further improvedin such a case.

Next, a preferred embodiment of the method for manufacturing aresin-molded semiconductor device according to the present inventionwill be described with reference to the accompanying drawings. FIGS.9(a) through 9(f) are cross-sectional views illustrating respectiveprocess steps for manufacturing the resin-molded semiconductor deviceaccording to the first embodiment.

First, as shown in FIG. 9(a), a terminal land frame 26, which includes aframe body 26 and a plurality of lands 28, is prepared. Each of thelands 28 is formed out of the frame body 26 to be connected to the framebody 26 via a thinned portion 27 and protrude out of the frame body 26.In this case, the terminal land frame is formed such that when the lands28 are pressed in a direction in which the lands 28 protrude out of theframe body 26, the thinned portions 27 are fractured and the lands 28are easily separable from the frame body 26.

Next, as shown in FIG. 9(b), the terminal land frame is placed with theprotruding portions of the lands 28 facing upward. A semiconductor chip30 is mounted on lands 28 a and 28 b of the first group among the lands28 with a conductive adhesive 29 (or insulating paste) introducedtherebetween, thereby bonding the semiconductor chip 30 and the lands 28a and 28 b of the first group together via the conductive adhesive 29.This process step corresponds to die bonding in an assembling process ofa resin-molded semiconductor device. in this process step, thesemiconductor chip 30 is bonded to the terminal land frame through aseries of steps of applying the conductive adhesive 29 to the terminalland frame, mounting the semiconductor chip 30 and heating.

In this case, the lands 28 are easily separable from the terminal landframe upon the application of a pressure in the direction in which thelands 28 protrude, i.e., a pressure applied upward from under the lowersurfaces of the lands 28. However, even when a pressure is applied inthe opposite direction, i.e., even if the lands 28 are pressed downwardfrom over the upper surfaces thereof, the lands 28 are less likely to beseparated from the terminal land frame. That is to say, these lands 28are separable only unidirectionally. Accordingly, even when a forcepressing the lands 28 downward is applied in mounting the semiconductorchip 30 on the terminal land frame, the lands 28 are not separated fromthe terminal land frame. Thus, the die bonding process step can beperformed safely.

Then, as shown in FIG. 9(c), the semiconductor chip 30 that has beenbonded onto the terminal land frame is electrically connected to lands28 c, 28 d, 28 e and 28 f of the second group to be external landelectrodes among the lands 28 via metal fine wires 31. This process stepis so-called “wire bonding”. The area at the upper surface of each ofthese lands 28, i.e., the area of the surface to which the metal finewire 31 is connected, is 100 μm φ or more. Accordingly, wire bonding canbe performed easily. In this process step, the lands 28 are also easilyseparable only by pressing them upward. Accordingly, even when a forcepressing the lands 28 downward is applied in connecting the metal finewires 31 to the upper surfaces of the lands 28, the lands 28 are notseparated from the terminal land frame. Thus, the wire bonding processstep can be performed safely, too.

Subsequently, as shown in FIG. 9(d), the semiconductor chip 30, metalfine wires 31 and so on, which have been mounted on the terminal landframe, are molded with a resin encapsulant 32. This process step isordinarily performed by a single-side-molding technique, i.e., transfermolding using a die assembly consisting of upper and lower dies divided.In this case, only a region over the surface of the terminal land frame,on which the semiconductor chip 30 has been mounted, is covered with theresin encapsulant 32, thereby obtaining a so-called “single-side-moldedstructure”. Since each of the lands 28 protrudes upward out of the bodyof the terminal land frame, that protruding portion is strongly held bythe resin encapsulant 32. Accordingly, although this is asingle-side-molded structure, the terminal land frame can be kept intight contact with the resin encapsulant 32.

Then, as shown in FIG. 9(e), the terminal land frame is fixed on afixing member, e.g., the periphery of the terminal land frame is fixedand the region molded with the resin encapsulant 32 is kept freelypressable. In such a state, the bottoms of the lands 28 are pressedupward from under the terminal land frame. For example, a pressure maybe applied from under the terminal land frame to the bottoms of thelands 28 by thrusting them up using thrusting pins with the periphery ofthe terminal land frame fixed. As a result, the thinned portions 27 witha very small thickness, which connect the lands 28 to the frame body 26,are fractured by the pressure resulting from that thrusting, and thelands 28 are separated from the frame body 26 of the terminal landframe. In performing such thrusting, part or all of the lands 28 may bethrust up. Specifically, either only the lands 28 located around thecenter, i.e., under the semiconductor chip 30, or those located aroundthe periphery may be thrust up. It should be noted that if some of thelands 28 are thrust up, that thrusting should be performed with such aforce as not peeling the other lands 28 themselves off the resinencapsulant 32 located at respective positions to which the thrustingforce is not applied. The lands 28 may be naturally separated from theframe body 26 of the terminal land frame by any means other thanthrusting. For example, the frame body 26 may be twisted or the resinencapsulant 32 may be sucked and pulled up.

By performing this process step of separating the lands 28 from theframe body 26 of the terminal land frame, the resin-molded semiconductordevice 33 shown in FIG. 9(f) is obtained. In this case, the respectiveportions of the frame body 26, where the lands 28 are not provided, arein loose contact with the resin encapsulant 32. Thus, when the lands 28are separated from the frame body 26, the resin-molded semiconductordevice 33 is easily separable from the frame body 26. Also, as shown inFIG. 9(f), the resin-molded semiconductor device 33 has such a structurethat the lands 28 are arranged on the bottom and protrude downward fromthe bottom of the resin encapsulant 32. Accordingly, the resin-moldedsemiconductor device 33 is already provided with a standoff height,which is required in mounting the device onto a motherboard. In thiscase, the standoff height of the resin-molded semiconductor device 33 issubstantially equal to the thickness B obtained by subtracting theprotrusion height A of the land 28 from the total thickness C of theframe body 26 as shown in FIG. 6. In this manner, a standoff heightneeded for the lands 28 to function as external land electrodes isensured. According to this embodiment, the thickness of the frame body26 may be 200 μm, while the protrusion height of the lands 28 may be inthe range from 140 μm to 180 μm, which is 70 to 90% of the thickness ofthe frame body 26. Thus, the standoff height may be in the range from 20μm to 60 μm, which is 10 to 30% of the thickness of the frame body 26.In this manner, it is possible to form land electrodes provided with astandoff height needed in mounting the device onto a motherboard.

The resin-molded semiconductor device may be separated from the framebody 26 not only by thrusting the lands 28 up in the above-describedmanner, but also by removing the frame body 26 itself with theresin-molded semiconductor device fixed. However, in view of theresultant product reliability, the former separation technique ispreferred according to this embodiment.

As described above, according to the terminal land frame of thisembodiment, only by mounting the semiconductor chip, molding the chip,wires and so on with the resin and then removing the frame body whilethrusting the lands upward, land electrodes, which are electricallyconnected to the semiconductor chip, can be arranged on the bottom ofthe resin-molded semiconductor device.

As a result, a face-mount semiconductor device is obtained, and thedevice can be mounted onto a motherboard with more reliability comparedto the conventional mounting technique using a leadframe. In addition,in the resin-molded semiconductor device, the standoff height of eachland protruding out of the resin encapsulant is obtained by subtractingthe height of the land protruding out of the frame body from thethickness of the terminal land frame used. That is to say, the standoffheight needed in mounting the device onto the motherboard is ensuredwhen the product is separated from the frame body. Accordingly, noadditional process step is required to ensure the standoff height.

Also, unlike a BGA-type semiconductor device, the resin-moldedsemiconductor device according to this embodiment does not use asubstrate provided with land electrodes, but is constructed using aframe body, which is a metal plate called a “terminal land frame”. Thus,the resin-molded semiconductor device of this embodiment is moreadvantageous than the conventional BGA-type semiconductor device interms of mass-productivity and cost effectiveness. Furthermore,according to this embodiment, a finished product can be easily obtainedonly by separating the frame body during the finishing process.Accordingly, various process steps of cutting and bending the leads,which are needed in the conventional process of separating the devicefrom the frame, are no longer necessary, thus eliminating the problemsof products damaged by the lead cutting and the restriction on cuttingaccuracy. Therefore, the present invention can provide an innovative,cost-effective technique by cutting down the number of necessary processsteps.

Embodiments 2

FIG. 10 is a plan view of a terminal land frame according to a secondembodiment of the present invention. FIG. 11 is a cross-sectional viewof the terminal land frame according to the second embodiment takenalong the line XI—XI shown in FIG. 10. The basic concept of the terminalland frame according to the second embodiment is the same as that of theterminal land frame according to the first embodiment.

As shown in FIGS. 10 and 11, the terminal land frame according to thesecond embodiment includes a frame body 10, which is a metal plate madeof copper or Alloy 42 that is used widely for leadframes. The terminalland frame further includes: a plurality of lands 12, which are arrangedon the frame body 10 to form a matrix pattern, connected to the framebody 10 via thinned portions 11 and protrude upward out of the framebody 10; and a die pad 34. That is to say, the frame body 10, lands 12,thinned portions 11 and die pad 34 are all made of a single metal plate.The terminal land frame is formed in such a manner that when a land 12is pressed upward on the bottom 12 a, the thinned portion 11 isfractured and the land 12 is separable from the frame body 10.

The terminal land frame according to the second embodiment has a similarconfiguration to that of the terminal land frame shown in FIGS. 1, 2 and3, but is characterized by further including the die pad 34 for mountinga semiconductor chip thereon.

Accordingly, when the land 12 and die pad 34 are pressed on the bottoms12 a and 34 a in such a direction as protruding the land 12 and the diepad 34 upward, the thinned portions 11 as indicated by the broken lineare fractured and the land 12 and the die pad 34 are separated from theframe body 10. In this case, the thinned portion 11 is a “linkageportion” formed by half-blanking the frame body 10 itself using ahalf-cutting member. That is to say, when parts of the frame body 10, inwhich the lands and die pad are to be formed, are blanked using blankingmembers, those parts are not blanked through completely, but blanking isstopped preferably at around a midway point. As a result, thosehalf-blanked parts protrude out of the frame body 10 to form the lands12 and die pad 34. And portions linking these lands 12 and the die pad34 to the frame body 10 are also formed as the thinned portions 11.

The protrusion height of the lands 12 and die pad 34 as measured fromthe upper surface of the frame body 10 is a half or more of thethickness of the frame body 10 itself. For example, according to thisembodiment, the thickness of the terminal land frame itself, i.e., thethickness of the frame body 10, may be 200 μm, while the protrusionheight of the lands 12 and die pad 34 may be in the range from 140 μm to180 μm, which is 70 to 90% of the thickness of the frame body 10.

Also, according to this embodiment, the terminal land frame is platedwith a plurality of metal layers, e.g., nickel (Ni), palladium (Pd) andgold (Au) layers, stacked one upon the other. In this manner, theterminal land frame may be plated if necessary.

The number of the lands 12 may be appropriately defined depending on thenumber of pins of the semiconductor chip to be mounted. Also, as shownin FIG. 10, the lands 12 may be successively formed out of the framebody 10 both horizontally and vertically alike. Unlike the conventionalleadframe, there is no need to separate individual chip mount regionsfrom each other or to provide any tie bars. Furthermore, the lands 12are illustrated as being circular when viewed from above, but may bepolygonal or rectangular. All the lands 12 within the terminal landframe may be of the same size.

Moreover, when a resin-molded semiconductor device is formed with thisterminal land frame using the lands 12 as land electrodes, only some ofthe lands 12 located around the periphery may be larger than the otherlands 12 to relax a stress, which is caused when the device is mountedonto a motherboard. The upper surface of the land 12 may be of such asize that a semiconductor chip can be bonded thereto via a metal finewire like a gold wire. In this embodiment, the size may be 100 μmφ ormore.

The terminal land frame according to the second embodiment includes noneof the conventional members called “inner leads” and “outer leads”.Instead, the terminal land frame includes lands 12 functioning as landelectrodes, which are arranged to form a matrix or hound's-tooth patternin its planar layout. Thus, a resin-molded semiconductor deviceincluding land electrodes on the bottom can be obtained easily by usingthis terminal land frame as will be described in detail later. Inaddition, according to this embodiment, the members functioning asexternal electrodes of a resin-molded semiconductor device are notradial leads as in a conventional leadframe, but dotted lands 12. Thus,these lands 12 may be disposed at any arbitrary positions in the planarlayout. Accordingly, these lands 12 may be placed more freely asexternal electrodes for a resin-molded semiconductor device, and it ispossible to cope with the increase in number of pins of a semiconductorchip.

Next, a method for manufacturing a terminal land frame according to thisembodiment will be described. The basic concept of the method formanufacturing a terminal land frame according to the second embodimentis the same as the manufacturing method according to the firstembodiment. The second embodiment is different from the first embodimentonly in that the die pad 34 is also formed at the same time when thelands 12 are formed.

Specifically, as shown in FIGS. 4 and 5, a metal plate, which has beenfixed at a predetermined position on a die, is pressed downward andhalf-blanked with blanking members. In this manner, parts of the metalplate are protruded into respective openings of the die and portions ofthe metal plate, with which the blanking members are now in contact, arehalf-cut, thereby forming the lands and die pad. That is to say, thelands and die pad are formed to remain connected to the metal plate viathe thinned portions and to protrude from the body of the metal plate.It should be noted that the number of the blanking member is notnecessarily one. Rather, it is more common to form a plurality of landsand die pads at a time using a plurality of blanking memberssimultaneously.

Also, the area of contact between that part of the metal plate, wherethe land or die pad should be formed, and the blanking member is smallerthan the area of the opening provided for the die. Furthermore, in theprocess step of forming the land or die pad to protrude out of the metalplate by getting that part of the metal plate pressed by the blankingmember, the upper surface of the land or die pad protruding from theupper surface of the metal plate is greater in area than the bottom ofthe land or die pad formed out of the bottom of the metal plate. Thus,the edges of the upper surface are curved, because these edges areplastically deformed and rounded.

In this structure, when the lands 12 and die pad 34 formed in this wayare pressed in the direction in which the lands 12 and die pad 34protrude, i.e., when a pressure is applied to the respective bottoms 12a and 34 a of the lands 12 and die pad 34, the lands 12 and die pad 34are easily separable from the body of the metal plate. On the otherhand, even when a pressure is applied to the respective upper surfaces12 b and 34 b of the lands 12 and die pad 34, the lands 12 and die pad34 are less likely to be separated from the metal plate. In other words,the lands 12 and die pad 34 are easily separable only by unidirectionalpressure.

According to this embodiment, when the lands 12 and die pad 34 areformed by half-blanking the metal plate, the protrusion height of thelands 12 and die pad 34 is a half or more of the thickness of the metalplate itself. For example, the thickness of the metal plate may be 200μm, while the protrusion height of the lands 12 and die pad 34 may be inthe range from 140 μm to 180 μm, which is 70 to 90% of the thickness ofthe metal plate itself. Accordingly, the lands 12 and die pad 34 formedto protrude are connected via the thinned portions with a thickness muchsmaller than that of the body of the metal plate. In this embodiment,the thickness of the thinned portion 11 may be in the range from 20 μmto 60 μm, which is 10 to 30% of the thickness of the metal plate itself.In such a case, the lands 12 and die pad 34 are easily separable fromthe metal plate by applying a pressure thereto in the direction in whichthe lands 12 and die pad 34 protrude.

According to this embodiment, the details of the half-blanking processstep, which are omitted in the foregoing description, are similar tothose described as for the first embodiment.

Next, a resin-molded semiconductor device using a terminal land frameaccording to this embodiment will be described with reference to theaccompanying drawings.

FIGS. 12 and 13 are cross-sectional view and bottom view, respectively,of the resin-molded semiconductor device according to the secondembodiment. FIG. 12 is a cross-sectional view of the device taken alongthe line XII—XII shown in FIG. 13. The resin-molded semiconductor deviceaccording to this embodiment is in a simple rectangular shape as viewedfrom above. Thus, the illustration of a plan view thereof is omittedherein.

As shown in FIGS. 12 and 13, the resin-molded semiconductor deviceaccording to this embodiment includes a semiconductor chip that has beenmounted using the terminal land frame. Specifically, a semiconductorchip 23 is mounted on the die pad 35 of the terminal land frame shown inFIGS. 10 and 11 via a conductive adhesive 22 such as silver paste. Onthe other hand, the lands 21, which are located around the periphery ofthe semiconductor chip 23, are electrically connected to thesemiconductor chip 23 via metal fine wires 24. Also, the lower half ofeach of these lands 21 and that of the die pad 35 protrudes downward outof the lower surface of a resin encapsulant 25. And the semiconductorchip 23, conductive adhesive 22, metal fine wires 24 and respectiveparts of the die pad 35 and lands 21 are molded with the resinencapsulant 25.

According to this embodiment, the height of the lower part of each land21 and the die pad 35 protruding out of the lower surface of the resinencapsulant 25 is substantially equal to the thickness B of thefracturable portion 20 as shown in FIG. 6, and is obtained bysubtracting the protrusion height A of the land 21 and the die pad 35from the total thickness C of the terminal land frame. This protrusionheight of the lower part of the land 21 and die pad 35 corresponds to astandoff height required in mounting the resin-molded semiconductordevice on a motherboard.

According to this embodiment, the semiconductor chip 23 is supported onthe die pad 35 and the lands 21 are used as external electrodes. On thebottom of the resin-molded semiconductor device, the lands 21 arearranged to form a land grid array.

In addition, in the resin-molded semiconductor device according to thisembodiment, the end face of each land 21 and the die pad 35, which iscovered (or molded) with the resin encapsulant 25, is greater in areathan the opposite end face thereof, which is not covered with the resinencapsulant 25 but protrudes. Furthermore, the edge portions of themolded end face of each of the lands 21 and die pad 35 are curved(plastically deformed and rounded). Accordingly, in the state shown inFIG. 12, the lands 21 and die pad 35 are substantially of an invertedtrapezoidal cross-sectional shape. By using such a structure, the lands21 and die pad 35 can be held by the resin encapsulant 25 more stronglyand can be in tighter contact with the resin encapsulant 25. Inaddition, the assembly can be mounted onto a motherboard withsufficiently high connection reliability maintained. Furthermore, if thethickness of the terminal land frame used is increased, then the contactarea between the lands 21 or die pad 35 and the resin encapsulant 25 canbe increased, thus enhancing the anchoring effects. As a result, thereliability can be further improved. Moreover, according to thisstructure, the semiconductor device can be mounted onto a motherboard onthe bottom. Accordingly, compared to the conventional technique ofmounting a device onto a motherboard using radial leads, mountreliability can be improved. As a result, reliability, which isequivalent to, or exceeding, that attained by a BGA-type semiconductordevice, is attainable.

Next, a preferred embodiment of the method for manufacturing aresin-molded semiconductor device according to the present inventionwill be described with reference to the accompanying drawings. The basicconcept of the method for manufacturing a resin-molded semiconductordevice using a terminal land frame according to the second embodiment isthe same as that of the method according to the first embodiment. FIGS.14(a) through 14(f) are cross-sectional views illustrating respectiveprocess steps for manufacturing the resin-molded semiconductor deviceaccording to the second embodiment.

First, as shown in FIG. 14(a), a terminal land frame, which includes aframe body 26, a plurality of lands 28 and a die pad 36, is prepared.Each of the lands 28 and die pad 36 is formed out of the frame body 26to be connected to the frame body 26 via a thinned portion 27 and toprotrude out of the frame body 26. In this case, the terminal land frameis formed such that when the lands 28 and die pad 36 are pressed in adirection in which the lands 28 and die pad 36 protrude out of the framebody 26, the thinned portions 27 are fractured and the lands 28 and diepad 36 are easily separable from the frame body 26.

Next, as shown in FIG. 14(b), the terminal land frame is placed with theprotruding portions of the lands 28 and die pad 36 facing upward. And asemiconductor chip 30 is mounted on the die pad 36 with a conductiveadhesive 29 (or insulating paste) introduced therebetween, therebybonding the semiconductor chip 30 and the die pad 36 together via theconductive adhesive 29. This process step corresponds to die bonding inan assembling process of a resin-molded semiconductor device. In thisprocess step, the semiconductor chip 30 is bonded to the terminal landframe through a series of steps of applying the conductive adhesive 29to the terminal land frame, mounting the semiconductor chip 30 andheating.

In this case, the lands 28 and die pad 36 are easily separable from theterminal land frame upon the application of a pressure in the directionin which the lands 28 and die pad 36 protrude, i.e., a pressure appliedupward from under the lower surfaces of the lands 28 and die pad 36.However, even when a pressure is applied in the opposite direction,i.e., even if the lands 28 and die pad 36 are pressed downward from overthe upper surfaces thereof, the lands 28 and die pad 36 are less likelyto be separated from the terminal land frame. That is to say, the lands28 and die pad 36 are separable only unidirectionally. Accordingly, evenwhen a force pressing the die pad 36 downward is applied in mounting thesemiconductor chip 30 on the terminal land frame, the die pad 36 is notseparated from the terminal land frame. Thus, the die bonding processstep can be performed safely.

Then, as shown in FIG. 14(c), the semiconductor chip 30 that has beenbonded onto the terminal land frame is electrically connected to thelands 28 via metal fine wires 31. This process step is so-called “wirebonding”. The area at the upper surface of each of these lands 28, i.e.,the area of the surface to which the metal fine wire 31 is connected, is100 μmφ or more. Accordingly, wire bonding can be performed easily. Inthis process step, the lands 28 are also easily separable only bypressing them upward. Thus, even when a force pressing the lands 28downward is applied in connecting the metal fine wires 31 to the uppersurfaces of the lands 28, the lands 28 are not separated from theterminal land frame. Therefore, the wire bonding process step can beperformed safely.

Subsequently, as shown in FIG. 14(d), the semiconductor chip 30, metalfine wires 31 and so on, which have been mounted on the terminal landframe, are molded with a resin encapsulant 32. This process step isordinarily performed by a single-side-molding technique, i.e., transfermolding using a die assembly consisting of upper and lower dies divided.In this case, only a region over the surface of the terminal land frame,on which the semiconductor chip 30 has been mounted, is covered with theresin encapsulant 32, thereby obtaining a so-called “single-side-moldedstructure”. Since the lands 28 and die pad 36 protrude upward out of thebody of the terminal land frame, those protruding portions are stronglyheld by the resin encapsulant 32. Accordingly, although this is asingle-side-molded structure, the terminal land frame can be kept intight contact with the resin encapsulant 32.

Then, as shown in FIG. 14(e), the terminal land frame is fixed on afixing member, e.g., the periphery of the terminal land frame is fixedand the region molded with the resin encapsulant 32 is kept freelypressable. In such a state, the lands 28 and die pad 36 are pressedupward on the bottom from under the terminal land frame. For example, apressure may be applied from under the terminal land frame by thrustingthe lands 28 and die pad 36 up via thrusting pins with the periphery ofthe terminal land frame fixed. As a result, the thinned portions 27 witha very small thickness, which connect the lands 28 and die pad 36 to theframe body 26, are fractured by the pressure resulting from thatthrusting, and the lands 28 and die pad 36 are separated from the framebody 26 of the terminal land frame.

By performing this process step of separating the lands 28 and die pad36 from the frame body 26 of the terminal land frame, the resin-moldedsemiconductor device 37 shown in FIG. 14(f) is obtained. As shown inFIG. 14(f), the resin-molded semiconductor device 37 has such astructure that the lands 28 and die pad 36 are arranged on the bottomand protrude downward out of the bottom of the resin encapsulant 32.Accordingly, the resin-molded semiconductor device 37 is alreadyprovided with a standoff height, which is required in mounting thedevice onto a motherboard. In this case, the standoff height of theresin-molded semiconductor device 37 is substantially equal to thethickness B obtained by subtracting the protrusion height A of the lands28 and die pad 36 from the total thickness C of the frame body 26 asshown in FIG. 6. In this manner, a standoff height needed for the lands28 to function as external land electrodes is ensured. According to thisembodiment, the thickness of the frame body 26 may be 200 μm, while theprotrusion height of the lands 28 may be in the range from 140 μm to 180μm, which is 70 to 90% of the thickness of the frame body 26.Accordingly, the standoff height may be in the range from 20 μm to 60μm, which is 10 to 30% of the thickness of the frame body 26. In thismanner, land electrodes provided with a standoff height needed inmounting the device onto a motherboard are obtained. Also, since the diepad 36 is connected to a radiating electrode of a motherboard, forexample, the heat generated inside the semiconductor chip 30 can bedissipated effectively.

By using the terminal land frame according to the second embodiment, thesame effects as those attained by the first embodiment are alsoattainable.

In addition, according to the second embodiment, the die pad is providedseparately from the lands unlike the first embodiment. Thus, if the diepad is connected to a radiating electrode of a motherboard, for example,the heat generated inside the semiconductor chip 30 can be dissipatedeffectively.

Embodiments 3

FIG. 15 is a plan view illustrating a terminal land frame according to athird embodiment of the present invention. FIG. 16 is a cross-sectionalview of the frame taken along the line XVI—XVI shown in FIG. 15. FIG. 17is a cross-sectional view illustrating a land shown in FIG. 16 to alarger scale.

As shown in FIGS. 15 through 17, the terminal land frame according tothe third embodiment includes a frame body 10, which is a metal platemade of copper or Alloy 42 that is used widely for leadframes. Theterminal land frame further includes a plurality of lands 12, which arearranged on the frame body 10 to form a matrix pattern corresponding tothe arrangement of bonding pads of a semiconductor chip, are connectedto the frame body 10 via thinned portions 11 and protrude upward out ofthe frame body 10. That is to say, the frame body 10, lands 12 andthinned portions 11 are all made of a single metal plate. The terminalland frame is formed in such a manner that when a land 12 is pressedupward on the bottom 12 a, the thinned portion 11 is fractured and theland 12 is separable from the frame body 10.

Also, as shown in FIG. 15, a large number of lands 12 are arranged toform a matrix pattern in its planar layout. Alternatively, these lands12 may be arranged to form a hound's-tooth check or checkerboard fashionor may be arranged at random in its planar layout. Anyway, it ispossible to adopt any arbitrary arrangement corresponding to that ofelectrode pads of a semiconductor chip to be mounted thereon.

As shown in FIG. 17, when the land 12 is pressed on the bottom 12 a insuch a direction as protruding the land 12 upward, the thinned portion11 as indicated by the broken line is fractured and the land 12 isseparated from the frame body 10. In this case, the thinned portion 11is a “linkage portion” formed by half-blanking the frame body 10 itselfusing a half-cutting member. That is to say, when part of the frame body10, in which a land is to be formed, is blanked using a blanking member,that part is not blanked through completely, but blanking is stoppedpreferably at around a midway point. As a result, that half-blanked partprotrudes out of the frame body 10 to form the land 12. And a portionlinking the land 12 to the frame body 10 is also formed as the thinnedportion 11. Accordingly, the thinned portion 11 is so thin that when theland 12 is pressed on the bottom 12 a in such a direction as protrudingthe land 12 upward, the thinned portion 11 is fractured easily.

The protrusion height of the land 12 as measured from the upper surfaceof the frame body 10 is a half or more of the thickness of the framebody 10 itself. That is to say, the frame body 10 is formed in such amanner that when a land 12 is pressed on the bottom 12 a upward in FIG.17, the thinned portion 11 is fractured and the land 12 is separablefrom the frame body 10.

According to this embodiment, the thickness of the terminal land frameitself, i.e., the thickness of the frame body 10, may be 200 μm, whilethe protrusion height of the land 12 may be in the range from 140 μm to180 μm, which is 70 to 90% of the thickness of the frame body 10. Itshould be noted that the thickness of the frame body 10 does not have tobe 200 μm, but may be about 400 μm if necessary. Also, according to thisembodiment, the protrusion height of the land 12 is supposed to be ahalf or more of the thickness of the frame body, e.g., 70 to 90% of thethickness of the frame body. Alternatively, the protrusion height may beless than a half of the thickness of the frame body. At any rate, theprotrusion height may be defined at such a value as making the thinnedportion 11 fracturable upon the application of pressure.

Furthermore, in the terminal land frame according to this embodiment,the top of the protruding part of the land 12 is somewhat expandedlaterally as a result of a type of pressing called “coining”.Accordingly, the upper surface of the land 12 is shaped flat like thatof a mushroom. Thus, when a semiconductor chip is mounted on theterminal land frame and molded with a resin, the lands 12 can be heldmore strongly by the resin encapsulant because the lands 12 are shapedlike mushrooms. As a result, the lands 12 can be in tighter contact withthe resin encapsulant, thus realizing highly reliable resin molding inspite of the single-side-molded structure thereof. It is noted that theprotruding part of the land 12 does not have to have its upper surfaceflattened like a mushroom, but may be in any arbitrary shape, e.g., likea crook, so long as the resin encapsulant can be anchored by the land12.

Also, according to this embodiment, the terminal land frame is platedwith a plurality of metal layers, e.g., nickel (Ni), palladium (Pd) andgold (Au) layers stacked one upon the other. In this manner, theterminal land frame may be plated if necessary. Plating the terminalland frame may be performed either after or before the metal plate isshaped to form the lands 12. Moreover, the roughness at the surface ofthe terminal land frame according to this embodiment is equal to or lessthan 0.1 μm. Although the surface of the terminal land frame never failsto get rugged by the formation of the lands 12, the surface roughness ofthe terminal land frame because of other reasons is preferably as smallas possible. This is because the roughness affects the ease of peelingthe terminal land frame from a resin during resin molding.

The number of the lands 12 may be appropriately defined depending on thenumber of pins (e.g., the number of electrode pads) of the semiconductorchip to be mounted. Also, as shown in FIG. 15, the lands 12 may besuccessively formed out of the frame body 10 both horizontally andvertically alike. Furthermore, the land 12 does not have to be circularas viewed from above, but may be polygonal or rectangular. All the lands12 within the terminal land frame may be of the same size. Moreover,when a resin-molded semiconductor device is formed with this terminalland frame using the lands 12 as land electrodes, only some of the lands12 located around the periphery may be larger than the other lands 12 torelax a stress caused when the device is mounted onto a motherboard. Theupper surface of the land 12 may be of such a size that a semiconductorchip can be bonded thereto via a metal fine wire like a gold wire. Inthis embodiment, the size may be 100 μmφ or more.

The terminal land frame according to this embodiment includes none ofthe conventional members called “inner leads”, “outer leads” and “diepad”. Instead, the terminal land frame includes lands 12 functioning asland electrodes, which are arranged to form a matrix or hound's-toothpattern in its planar layout. Thus, a resin-molded semiconductor deviceincluding land electrodes on the bottom can be obtained easily by usingthis terminal land frame as will be described in detail later. Inaddition, according to this embodiment, the members functioning asexternal electrodes of a resin-molded semiconductor device are notradial leads as in a conventional leadframe, but dotted lands 12. Thus,these lands 12 may be disposed at any arbitrary positions in the planarlayout. Accordingly, these lands 12 may be placed more freely as theexternal electrodes of a resin-molded semiconductor device, and it ispossible to cope with the increase in number of pins of a semiconductorchip. The arrangement pattern of the lands 12 is arbitrarily selectablein accordance with the number of pins of a semiconductor chip to bemounted. Thus, it is naturally possible to arrange the lands 12 in lineas in the conventional leadframe.

The terminal land frame according to the third embodiment ischaracterized in that the arrangement of the lands 12 is in accord withthat of electrode pads of a semiconductor chip to be mounted unlike thefirst embodiment.

FIG. 18 is a plan view of a semiconductor chip 44 used in the thirdembodiment. As shown in FIG. 18, electrode pads 43 like area pads areprovided on the upper surface of the semiconductor chip 44. The terminalland frame with the arrangement of lands 12 as shown in FIG. 15 isapplicable to the semiconductor chip 44 with the arrangement ofelectrode pads 43 like area pads as shown in FIG. 18.

FIG. 19 is a plan view of a semiconductor chip 45 used in a modifiedexample of the third embodiment. As shown in FIG. 19, electrode pads 43are arranged around the periphery of the upper surface of thesemiconductor chip 45.

FIG. 20 is a plan view of a terminal land frame applicable to thesemiconductor chip 45 with the electrode pads 43 arranged around theperiphery thereof such as that shown in FIG. 19. That is to say, in theterminal land frame according to this modified example, the lands 12 arearranged in line on each side of a square on the frame body 10 so as tocorrespond to the arrangement of electrode pads 43 around the periphery.

In the following description of the third embodiment, it is supposedthat the semiconductor chip 44 shown in FIG. 18 is used for the terminalland frame shown in FIG. 15 as a typical example.

Next, a method for manufacturing the terminal land frame according tothe third embodiment will be described.

According to the third embodiment, the lands 12 are formed by performingthe half-blanking process step during the manufacturing process of theterminal land frame in exactly the same way as described in the firstembodiment with reference to FIGS. 4 through 6. In addition, thethicknesses of respective portions are also just as already described.Thus, the illustration and description of the half-blanking process stepwill be omitted herein.

Next, a resin-molded semiconductor device according to the thirdembodiment will be described with reference to the accompanyingdrawings.

FIGS. 21 and 22 are respectively cross-sectional view and bottom view ofa resin-molded semiconductor device according to the third embodiment.FIG. 21 is a cross-sectional view of the device taken along the lineXXI—XXI shown in FIG. 22. The resin-molded semiconductor deviceaccording to this embodiment is in a simple rectangular shape as viewedfrom above. Thus, the illustration of a plan view thereof is omittedherein.

As shown in FIGS. 21 and 22, the resin-molded semiconductor deviceaccording to this embodiment includes a semiconductor chip that has beenmounted using the terminal land frame. Specifically, a semiconductorchip 44 is mounted on the lands 21 via a conductive adhesive 22 such assilver paste (or insulating paste) as shown in FIG. 21. Also, the lowerhalf of each of these lands 21 protrudes downward from the lower surfaceof a resin encapsulant 25. And the semiconductor chip 44, conductiveadhesive 22 and respective parts of the lands 21 are molded with theresin encapsulant 25.

According to this embodiment, the height of the lower part of each land21 protruding out of the lower surface of the resin encapsulant 25 issubstantially equal to the thickness B of the fracturable portion 20shown in FIG. 6, and is obtained by subtracting the protrusion height Aof the land 21 from the total thickness C of the terminal land frame.This protrusion height of the lower part of the land 21 corresponds to astandoff height required in mounting the resin-molded semiconductordevice on a motherboard.

In the resin-molded semiconductor device according to this embodiment,the semiconductor chip 44 is mounted facedown on the lands 21, therebyelectrically connecting the electrode pads of the semiconductor chip 44to the lands 21. That is to say, according to the third embodiment, nometal fine wires are used unlike the first and second embodiments.

On the bottom of the resin-molded semiconductor device, the lands 21 arearranged to form a land grid array. The area of the resin-moldedsemiconductor device is substantially equal to that of the semiconductorchip 44. In other words, the size of this package is approximately equalto that of the chip. Also, unlike the conventional resin-moldedsemiconductor device using a leadframe, the upper surface area of theland 21 only needs to be as large as that of the electrode pad 43 of thesemiconductor chip 44, i.e., about 100 μmφ. In addition, the height ofthe land 21 may be about 140 μm to about 180 μm. Accordingly, theelectrode pads 43 can be arranged at a high density, thus realizing adownsized and thinned resin-molded semiconductor device. Moreover, thestructure according to this embodiment can cope with multiple-pinimplementation and contribute to the realization of a high-densityface-mount resin-molded semiconductor device. Furthermore, even afterresin molding has been performed, the resin-molded semiconductor devicecan be as thin as 1 mm or less, e.g., about 500 μm.

In addition, in the resin-molded semiconductor device according to thisembodiment, the end face of the land 21, which is covered (or molded)with the resin encapsulant 25, is greater in area than the opposite endface thereof, which is not covered with the resin encapsulant 25 butprotrudes. Furthermore, the edge portions of the molded end face of theland 21 are curved (or plastically deformed and rounded). Accordingly,in the state shown in FIG. 21, the land 21 is substantially of aninverted trapezoidal cross-sectional shape. By using such a structure,the land 21 can be held by the resin encapsulant 25 more strongly andcan be in tighter contact with the resin encapsulant 25. In addition,the assembly can be mounted onto a motherboard with sufficiently highconnection reliability maintained. Furthermore, if the thickness of theterminal land frame used is increased, then the contact area between theland 21 and the resin encapsulant 25 can be increased, thus enhancingthe anchoring effects. As a result, the reliability can be furtherimproved.

According to this embodiment, the semiconductor chip 44 is entirelymolded within the resin encapsulant 25. Alternatively, the backside ofthe semiconductor chip 44 may be exposed by injecting the resinencapsulant only into the gap between the semiconductor chip 44 and thelands 21 and molding them. Also, the semiconductor chip 44 is connectedto the lands 21 via the conductive adhesive 22. As an alternative,protruding electrodes such as Au bump electrodes, preferably two-stepprotruding electrodes, may be formed in advance on the electrode pads 43of the semiconductor chip 44 and a conductive adhesive may be applied tothese protruding electrodes to electrically connect the electrode pads43 and the lands 21 together. In such a case, since the protrudingelectrodes have a stepped structure, the conductive adhesive can be heldby the protruding electrodes more strongly, and the conductive adhesivedoes not stick out between the electrode pad and the land, thusimproving the connection reliability.

Next, a method for manufacturing a resin-molded semiconductor deviceaccording to the third embodiment will be described with reference tothe accompanying drawings. FIGS. 23(a) through 23(e) are cross-sectionalviews illustrating respective process steps for manufacturing theresin-molded semiconductor device according to the third embodiment.

First, as shown in FIG. 23(a), a terminal land frame, which includes aframe body 26 and a plurality of lands 28, is prepared. Each of thelands 28 is formed out of the frame body 26 to be connected to the framebody 26 via a thinned portion 27 and to protrude out of the frame body26. In this case, the terminal land frame is formed such that when thelands 28 are pressed in a direction in which the lands 28 protrude outof the frame body 26, the thinned portions 27 are fractured and thelands 28 are easily separable from the frame body 26.

Next, as shown in FIG. 23(b), the terminal land frame is placed with theprotruding portions of the lands 28 facing upward, and the semiconductorchip 30 is disposed facedown over the terminal land frame with the side,on which the electrode pads (not shown) are formed, facing downward. Andthe semiconductor chip 30 is mounted on the lands 28 with a conductiveadhesive 29 introduced therebetween, thereby bonding the respectiveelectrode pads of the semiconductor chip 30 to the associated lands 28via the conductive adhesive 29. This process step corresponds toflip-chip bonding in an assembling process of a semiconductor device. Inthis process step, the semiconductor chip 30 is bonded to the terminalland frame through a series of steps of applying the conductive adhesive29 to the terminal land frame, mounting the semiconductor chip 30facedown and heating.

In this case, the lands 28 are easily separable from the terminal landframe upon the application of a pressure in the direction in which thelands 28 protrude, i.e., a pressure applied from under the lowersurfaces of the lands 28. However, even when a pressure is applied inthe opposite direction, i.e., even if the lands 28 are pressed from overthe upper surfaces thereof, the lands 28 are less likely to be separatedfrom the terminal land frame. That is to say, these lands 28 areseparable only unidirectionally. Accordingly, even when a force pressingthe lands 28 downward is applied in mounting the semiconductor chip 30on the terminal land frame, the lands 28 are not separated from theterminal land frame. Thus, flip-chip bonding can be performed safely.

Then, as shown in FIG. 23(c), the semiconductor chip 30, which has beenbonded facedown on the terminal land frame, and the bonding portions aremolded with a resin encapsulant 32. This process step is ordinarilyperformed by a single-side-molding technique, i.e., transfer moldingusing a die assembly consisting of upper and lower dies divided. In thiscase, only a region over the surface of the terminal land frame, onwhich the semiconductor chip 30 has been mounted, is covered with theresin encapsulant 32, thereby obtaining a so-called “single-side-moldedstructure”. Since each of the lands 28 protrudes upward out of the bodyof the terminal land frame, that protruding portion is strongly held bythe resin encapsulant 32. Accordingly, although this is asingle-side-molded structure, the terminal land frame can be kept intight contact with the resin encapsulant 32.

In this case, the assembly may be molded with the resin 32 onlypartially by injecting the resin encapsulant 32 into the gap between thesemiconductor chip 30 and the lands 28 of the terminal land frame usinga nozzle, syringe or the like. In the semiconductor device formed inthis way, the backside of the semiconductor chip 30 is not covered withthe resin encapsulant 32 but exposed to the air. As a result, a packagewith excellent radiative properties can be obtained.

Then, as shown in FIG. 23(d), the terminal land frame is fixed on afixing member, e.g., the periphery of the terminal land frame is fixedand the region molded with the resin encapsulant 32 is kept freelypressable. In such a state, the lands 28 are pressed upward on thebottom from under the terminal land frame. For example, a pressure maybe applied from under the terminal land frame by thrusting the lands 28up using thrusting pins with the periphery of the terminal land framefixed. As a result, the thinned portions 27 with a very small thickness,which connect the lands 28 to the frame body 26, are fractured by thepressure resulting from that thrusting, and the lands 28 are separatedfrom the frame body 26 of the terminal land frame. In performing suchthrusting, part or all of the lands 28 may be thrust up. Specifically,either only the lands 28 located around the center, i.e., under thesemiconductor chip 30 or those located around the periphery may bethrust up. It should be noted that if some of the lands 28 are thrustup, that thrusting should be performed with such a force as not peelingthe lands 28 themselves off the resin encapsulant 32 located atrespective positions to which the thrusting force is not applied. Thelands 28 may be naturally separated from the frame body 26 of theterminal land frame by any means other than thrusting. For example, theframe body 26 may be twisted or the resin encapsulant 32 may be suckedand pulled up.

By performing this process step of separating the lands 28 from theframe body 26 of the terminal land frame, the resin-molded semiconductordevice 33 shown in FIG. 23(e) is obtained. In this case, the respectiveportions of the frame body 26, where the lands 28 are not provided, arein loose contact with the resin encapsulant 32. Thus, when the lands 28are separated from the frame body 26, the resin-molded semiconductordevice 33 is easily separable from the frame body 26. Also, as shown inFIG. 23(e), the resin-molded semiconductor device 33 has such astructure that the lands 28 are arranged on the bottom and protrudedownward from the bottom of the resin encapsulant 32. Accordingly, theresin-molded semiconductor device 33 is already provided with a standoffheight, which is required in mounting the device onto a motherboard. Inthis case, the standoff height of the resin-molded semiconductor device33 is substantially equal to the thickness B obtained by subtracting theprotrusion height A of the land 28 from the total thickness C of theframe body 26 as shown in FIG. 6. In this manner, a standoff heightneeded for the lands 28 to function as external land electrodes isensured. According to this embodiment, the thickness of the frame body26 may be 200 μm, while the protrusion height of the lands 28 may be inthe range from 140 μm to 180 μm, which is 70 to 90% of the thickness ofthe frame body 26. Accordingly, the standoff height may be in the rangefrom 20 μm to 60 μm, which is 10 to 30% of the thickness of the framebody 26. In this manner, land electrodes provided with a standoff heightneeded in mounting the device onto a motherboard are obtained.

As described above, according to the terminal land frame of thisembodiment, only by flip-chip mounting the semiconductor chip, moldingthe chip and so on with the resin and then removing the terminal landframe while thrusting the lands upward, land electrodes, which areelectrically connected to the semiconductor chip, can be arranged on thebottom of the resin-molded semiconductor device.

As a result, a face-mount semiconductor device is obtained, and thedevice can be mounted onto a motherboard with more reliability comparedto the conventional mounting technique using a leadframe. In addition,in the resin-molded semiconductor device, the standoff height of eachland protruding out of the resin encapsulant is obtained by subtractingthe height of the land protruding out of the frame body from thethickness of the terminal land frame used. Since the standoff heightneeded in mounting the device onto the motherboard is ensured when theproduct is separated from the frame body, no additional process step isrequired to ensure the standoff height.

Also, unlike a BGA-type semiconductor device, the resin-moldedsemiconductor device according to this embodiment does not use asubstrate provided with land electrodes, but is constructed using aframe body made of a metal plate called a “terminal land frame”. Thus,the resin-molded semiconductor device of this embodiment is moreadvantageous than the conventional BGA-type semiconductor device interms of mass-productivity and cost effectiveness. Furthermore,according to this embodiment, a finished product can be easily obtainedonly by separating the frame body. Accordingly, various process steps ofcutting and bending the leads, which are needed in the conventionaltechnique of separating the device from the frame, are no longernecessary, thus eliminating the problems of products damaged by the leadcutting and the restriction on cutting accuracy. Therefore, the presentinvention can provide an innovative, cost-effective technique by cuttingdown the number of necessary process steps.

Furthermore, the lands are separated from the frame body by applying apressure such as thrusting force thereto in the foregoing description.However, the lands may also be separated from the frame body at thethinned portions by any technique other than thrusting, e.g., the framebody may be peeled off with the resin-molded semiconductor device fixed.Accordingly, any of various means for effectively cutting the thinnedportions, which connect the lands to the frame body, may be adopted.

What is claimed is:
 1. A terminal land frame comprising: a frame body; aplurality of lands, each one of said plurality of lands beingsubstantially as thick as the frame body, at least part of each one ofsaid plurality of lands having a projection protruding out of the framebody and a recess part depressing inwardly from the frame body formed bypressing on the opposite side of the projection; and a plurality ofthinned portions, each one of said plurality of thinned portions havinga thickness of 10% to 30% of the thickness of the frame body andconnecting the frame body to associated one of the lands, wherein theframe body, the lands and the thinned portions are all made of a singlemetal plate, and wherein when each one of said plurality of lands ispressed in a direction in which the land protrudes, associated one ofthe thinned portions is fractured and the land is separable from theframe body.
 2. The terminal land frame of claim 1, wherein the top ofthe part of each said land, which protrudes from the frame body, islaterally expanded and shaped like a mushroom.
 3. The terminal landframe of claim 1, wherein the top face of the part of each said land,which protrudes from the frame body, is greater in area than anotherface of the land.
 4. A terminal land frame comprising: a frame body; adie pad being substantially as thick as the frame body and including aprojection protruding out of the frame body and a first recess partdepressing inwardly from the frame body formed by pressing on theopposite side of the projection; a plurality of lands, each one of saidplurality of lands being substantially as thick as the frame body andincluding a projection protruding out of the frame body and a secondrecess part depressing inwardly from the frame body formed by pressingon the opposite side of the projection; a first thinned portion, whichhas a thickness of 10% to 30% of the thickness of the frame body,connecting the frame body and the die pad together; and a plurality ofsecond thinned portions, each one of said plurality of second thinnedportions having a thickness of 10% to 30% of the thickness of the framebody and connecting the frame body to associated one of the lands,wherein the frame body, the die pad, the lands and the first and secondthinned portions are all made of a single metal plate, and wherein whenthe die pad and each one of said plurality of lands are pressed in adirection in which the die pad and the land protrude, the first thinnedportion and associated one of the second thinned portions are fracturedand the die pad and the land are separable from the frame body.
 5. Theterminal land frame of claim 4, wherein the top of the first part of thedie pad and the top of the second part of each of said land arelaterally expanded and shaped like a mushroom.
 6. The terminal landframe of claim 4, wherein the top face of the first part of the die padis greater in area than another face of the first part of the die pad,which is opposite to the top face, and the top face of the first parthas curved edges, and wherein the top face of the second part of eachsaid land is greater in area than another face of the second part, whichis opposite to the top face, and the top face of the second part hascurved edges.
 7. A resin-molded semiconductor device formed by using aterminal land frame, the terminal land frame including: a metallic framebody; a plurality of lands including first and second groups of lands,each one of said plurality of lands being substantially as thick as theframe body, at least part of each one of said plurality of lands havinga projection protruding out of the frame body and a recess partdepressing inwardly from the frame body formed by pressing on theopposite side of the projection; and a plurality of thinned portions,each one of said plurality of thinned portions having a thickness of 10%to 30% of the thickness of the frame body and connecting the frame bodyto associated one of the lands, the frame body, the lands and thethinned portions are all made of a single metal plate, the semiconductordevice comprising: a semiconductor chip being mounted on the first groupof lands and having a plurality of electrode pads; a plurality ofconnection members, each one of said plurality of connection memberselectrically connecting each one of said plurality of lands of thesecond group to associated one of the electrode pads; and a resinencapsulant for molding the semiconductor chip, the connection membersand respective upper halves of the lands, each said upper halfcorresponding to the part of the associated land that protrudes out ofthe frame body, wherein a lower half of each one of said plurality oflands other than the upper half thereof is not covered with the resinencapsulant but protrudes downward out of the lower surface of the resinencapsulant.
 8. The device of claim 7, wherein the top face of the upperhalf of each said land, which is buried in the resin encapsulant, isgreater in area than the bottom face of the lower half thereof, and thetop face of the upper half has curved edges.
 9. A resin-moldedsemiconductor device formed by using a terminal land frame, the terminalland frame including: a metallic frame body; a die pad beingsubstantially as thick as the frame body and including a first partprotruding out of the frame body; a plurality of lands, each one of saidplurality of lands being substantially as thick as the frame body andincluding a second part protruding out of the frame body; a firstthinned portion, which has a thickness of 10% to 30% of the thickness ofthe frame body, connecting the frame body and the die pad together; anda plurality of second thinned portions, each one of said plurality ofsecond thinned portions having a thickness of 10% to 30% of thethickness of the frame body and connecting the frame body to associatedone of the lands, the frame body, the die pad, the lands and the firstand second thinned portions are all made of a single metal plate, thesemiconductor device comprising: a semiconductor chip being mounted onthe die pad and having a plurality of electrode pads; a plurality ofconnection members, each one of said plurality of connection memberselectrically connecting each one of said plurality of lands toassociated one of the electrode pads of the semiconductor chip; and aresin encapsulant for molding the semiconductor chip, the connectionmembers, a first upper half corresponding to the first part of the diepad protruding out of the frame body, and respective second upper halvescorresponding to the second parts of the lands protruding out of theframe body, wherein a first lower half, which is the remaining portionof the die pad other than the first upper half, and second lower halves,each of which is the remaining portion of associated one of the landsother than associated one of the second upper halves, are not coveredwith the resin encapsulant but protrude downward out of the lowersurface of the resin encapsulant, and the first lower half and thesecond lower halves have a recess part depressing inwardly from theframe body.
 10. The device of claim 9, wherein the top face of the firstupper half of the die pad, which is buried in the resin encapsulant, isgreater in area than the bottom face of the first lower half thereof,and the top face of the first upper half has curved edges, and whereinthe top face of the second upper half of each said land, which is buriedin the resin encapsulant, is greater in area than the bottom face of thesecond lower half thereof, and the top face of the second upper half hascurved edges.
 11. A resin-molded semiconductor device formed by using aterminal land frame, the terminal land frame including: a metallic framebody; a plurality of lands, each one of said plurality of lands beingsubstantially as thick as the frame body, at least part of each one ofsaid plurality of lands having a projection protruding out of the framebody and a recess part depressing inwardly from the frame body formed bypressing on the opposite side of the projection; and a plurality ofthinned portions, each one of said plurality of thinned portions havinga thickness of 10% to 30% of the thickness of the frame body andconnecting the frame body to associated one of the lands, the framebody, the lands and the thinned portions are all made of a single metalplate, the semiconductor device comprising: a semiconductor chip beingmounted on the lands and having a plurality of electrode pads connectedto the lands; and a resin encapsulant for molding the semiconductor chipand respective upper halves of the lands, each said upper halfcorresponding to the part of the associated land that protrudes out ofthe frame body, wherein a lower half of each one of said plurality oflands other than the upper half thereof is not covered with the resinencapsulant but protrudes downward out of the lower surface of the resinencapsulant.
 12. The device of claim 11, wherein the top face of theupper half of each said land, which is buried in the resin encapsulant,is greater in area than the bottom face of the lower half thereof, andthe top face of the upper half has curved edges.
 13. The device of claim11, further comprising: the same number of protruding electrodes as thatof the electrode pads of the semiconductor chip, each said protrudingelectrode being formed on associated one of the electrode pads; and aconductive adhesive for electrically connecting the protrudingelectrodes to the lands.
 14. A terminal land frame comprising: a framebody; a plurality of lands, each one of said plurality of lands beingsubstantially as thick as the frame body, at least part of each one ofsaid plurality of lands having a projection protruding out of the framebody and a recess part depressing inwardly from the frame body formed bypressing on the opposite side of the projection; and a plurality ofthinned portions, each one of said plurality of thinned portions havinga thickness of 10% to 30% of the thickness of the frame body andconnecting the frame body to associated one of the lands, wherein theframe body, the lands and the thinned portions are all made of a singlemetal plate, and wherein when each one of said plurality of lands ispressed in a direction in which the land protrudes, associated one ofthe thinned portions is fractured and the land is separable from theframe body, and the part of each one of said plurality of landsprotruding out of the frame body remains in a resin encapsulant of aresin-molded semiconductor device.
 15. The terminal land frame of claim14, wherein at least one of the lands function as an external electrode.16. The terminal land frame of claim 14, wherein at least one of thelands function as a die pad.